EP1015912B1 - Acoustic source i - Google Patents

Acoustic source i Download PDF

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Publication number
EP1015912B1
EP1015912B1 EP97906348A EP97906348A EP1015912B1 EP 1015912 B1 EP1015912 B1 EP 1015912B1 EP 97906348 A EP97906348 A EP 97906348A EP 97906348 A EP97906348 A EP 97906348A EP 1015912 B1 EP1015912 B1 EP 1015912B1
Authority
EP
European Patent Office
Prior art keywords
side elements
sound emitting
acoustic source
emitting surfaces
source according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP97906348A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP1015912A1 (en
Inventor
Rune Tenghamn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PGS Geophysical AS
Original Assignee
Unaco Systems AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Unaco Systems AB filed Critical Unaco Systems AB
Publication of EP1015912A1 publication Critical patent/EP1015912A1/en
Application granted granted Critical
Publication of EP1015912B1 publication Critical patent/EP1015912B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/02—Generating seismic energy
    • G01V1/143—Generating seismic energy using mechanical driving means, e.g. motor driven shaft
    • G01V1/145—Generating seismic energy using mechanical driving means, e.g. motor driven shaft by deforming or displacing surfaces, e.g. by mechanically driven vibroseis™
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
    • G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
    • G10K9/121—Flextensional transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/44—Special adaptations for subaqueous use, e.g. for hydrophone
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/30—Assessment of water resources

Definitions

  • This invention relates in general to acoustic sources for the generation of soundwaves in water, especially soundwaves with low frequencies, e.g. for use in seismic studies at sea.
  • Such sources being used in generating soundwaves in water, may be described in different ways, such as seismic emitters, flextensional sources or acoustic vibrators, such as sonars.
  • the acoustic source according to the invention may preferably be used in relation to such sound- or tone-emitters, since the soundwaves emitted into the water may be reflected from the sea bottom and geological formations beneath it, with succeeding monitoring and detection using hydrophones or geophones of different types.
  • the invention is especially aimed at a certain embodiment of sound emitting membranes or shells in acoustic sources, and the present embodiment may be considered to be related to certain types of flextensional emitters.
  • Flextensional emitters are described in many publications, one example being L.H. Royster:"The flextensional concept. A new approach to the design of underwater acoustic transducers", Appl.Acoust. 3 (1970), pp 117-226. Other examples are G. Bromfield: “Class IV flextensional transducers”, Proceedings Second International Workshop on Power Transducers, Toulon, (France) June 1990, and G. Brigham and B. Glass: “Present status in flextensional transducer technology", J. Acoust. Soc. A., 68(1980), pp. 1046-1052.
  • flextensional shells are based on the principle of changes in volume in a vibrating, elliptic shell.
  • the long axis of an ellipse When the long axis of an ellipse is set into vibration the length of the short axis will also vibrate, but with a much larger amplitude. This makes the ellipse shape an effective generator of acoustic energy at low frequencies.
  • the basic resonance frequency of the elliptic shell is so low that the length of the shell is small when compared to the wavelength in water.
  • a limiting factor for this kind of shells are the mechanical tensions forced upon the shell when large vibrational amplitudes are to be obtained.
  • Normally aluminum or glass-fibre armed plastic is used as shell material.
  • the use of such shells are also limited as a result of their complex shape, which lead to complicated manufacturing methods.
  • This last embodiment comprises in short two octagonal end plates joined together with eight rod-shaped elements having a concave curvature and being positioned in an essentially circular or polygonal arrangement surrounding an axis of symmetry.
  • a major problem with this design is the many slits between the rod elements, and the question of sealing and possible contact between these elements.
  • the novelty of this invention is primarily related to the fact that the sound emitting surfaces are formed by two curved membrane-like plate members having width and height dimensions of comparable sizes and being mounted back-to-back, that the plate-like end pieces have essentially rectangular shapes with a first pair of opposite side edges connected to the end parts of the plate members, and that another pair of side edges on each end piece, as well as the side edges of the plate members are connected to two side pieces which close the acoustic source on each side, preferably in a sealing way.
  • An object of this invention is to provide an improved acoustic source, which through a simple and suitable embodiment provides a dependable and reliable source unit, at the same time having a high acoustic efficiency.
  • this invention is thus based on an acoustic source primarily for use in seismic studies at sea, with sound emitting surfaces adapted to be put into sound emitting movement to and from each other using a drive unit in an, in itself, known way.
  • the sound emitting surfaces are formed by two curved plate members essentially symmetrically positioned in relation to the axis of the source forming a convex cross section with the upper and the lower edges converging towards each other, that the upper and lower edges of the sound emitting surfaces are flexibly connected to two corresponding side elements positioned between them, and that the source comprises a rigid frame, preferably for the support of the drive assembly, comprising at least two rigid sliding rods stretching between the side elements, and that covers are mounted on the slide rods being adapted to cover essentially all of the side elements and possibly parts of the sound emitting surfaces in order to form rigid, covering surfaces with constant distance between them.
  • Figure 1 shows an embodiment of the invention with an essentially circular cross section comprising sound emitting surfaces 2 being in their upper 4 and lower 5 ends flexibly connected to side elements 6.
  • the side elements 6 are covered with covers 10.
  • the drive assembly 3,12,13 the sound emitting surfaces are respectively pushed away from and towards each other, and generates thus a pressure wave which may propagate through water.
  • the side elements 6 in an acoustic source with the shape shown in figure 1 would generate acoustic waves with a phase being opposite compared to the acoustic waves generated from the sound emitting surfaces 2.
  • the acoustic source is provided with covers 10 covering the side elements 6 and keeping a constant distance from each other using the slide rods 8 and the frame 7.
  • the slide rods 8 have a sliding, and possibly sealed, connection to the side elements, using slide bearings.
  • the drive unit 3,12,13 is mounted inside a frame 7.
  • the frame 7 is held in position inside the source using the slide rods 8 drawn vertically in the drawings.
  • Preferably horizontal slide rods 11 are also used to lock the position of the frame in the vertical direction. These may for example be mounted using slide bearings to the outer drive parts 3. If other types of drive units are used these second slide rods 11 may be mounted in suitable suspension points or in relation to, but usually not through, the sound emitting surfaces.
  • the covers 10 are preferably tightly connected to the source with sealing strips or similar decices, so that the movements of the side elements do not propagate through the surrounding water.
  • the signal from the sound emitting surfaces 2 will not be distorted by signals from the side elements 6.
  • FIG. 2 a source in shown with an essentially elliptic cross section, where the side elements are made small by using hinges, or similar flexible couplings, connecting the upper and lower edges 4,5, respectively, of the sound emitting surfaces.
  • FIG. 2 a source in shown with an essentially elliptic cross section, where the side elements are made small by using hinges, or similar flexible couplings, connecting the upper and lower edges 4,5, respectively, of the sound emitting surfaces.
  • a similar solution in which the side elements 6 comprises two hinges, or rows of hinges, each connecting the side elements with the edges 4,5 of one of the sound emitting surfaces 2, may of course also be contemplated.
  • the acoustic sources shown in the drawings are equipped with electrodynamic drive units. These are described in detail in Norwegian patent application no. 95.2605, (corresponding to International patent application no. PCT/NO96/00131).
  • the drive units comprise pairs of electromagnetic and magnetic elements 3,12 being given a relative movement in relation to each other by applying a varying electric current.
  • One of these parts 12 are mounted firmly in relation to a frame 7, and the other 3 is mounted on a transmission device 13.
  • a movement of the second part 3 gives the transmission device a movement which propagates to the side elements 6, which in turn moves the sound emitting surfaces 2.
  • Other types of known drive units for example based on electric rotation motors like the ones described in Norwegian patent application no. 95.1949 (corresponding to International patent application no. PCT/NO96/00119) or Norwegian patent no. 176.457 (corresponding to International patent application no. PCT/NO94/00057), may of course also be used.
  • the dimensions of the acoustic source in the longitudinal direction will vary, depending on use, and is not important to the invention.
  • the number of slide rods 8,11, drive units 3,12,13 an similar will depend on the length of the source.
  • the slide rods are shown in a position centrally on the covers.
  • Other solutions, such as slide rods positioned in pairs side by side along the length of the source, will also be possible.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Remote Sensing (AREA)
  • Environmental & Geological Engineering (AREA)
  • Signal Processing (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Multimedia (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
EP97906348A 1996-04-30 1997-03-05 Acoustic source i Expired - Lifetime EP1015912B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
NO961764 1996-04-30
NO961764A NO303472B1 (no) 1996-04-30 1996-04-30 Akustisk sender
PCT/NO1997/000063 WO1997041453A1 (en) 1996-04-30 1997-03-05 Acoustic source i

Publications (2)

Publication Number Publication Date
EP1015912A1 EP1015912A1 (en) 2000-07-05
EP1015912B1 true EP1015912B1 (en) 2002-06-05

Family

ID=19899330

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97906348A Expired - Lifetime EP1015912B1 (en) 1996-04-30 1997-03-05 Acoustic source i

Country Status (6)

Country Link
US (1) US6041888A (no)
EP (1) EP1015912B1 (no)
AU (1) AU2106897A (no)
DE (1) DE69713169D1 (no)
NO (1) NO303472B1 (no)
WO (1) WO1997041453A1 (no)

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2786957B1 (fr) * 1998-12-07 2001-02-23 Sfim Ind Actionneur piezo-electrique ou electrostrictif
FI119455B (fi) * 2003-06-18 2008-11-14 Patria Advanced Solutions Oy Vedenalainen äänilähde
US7551518B1 (en) 2008-02-26 2009-06-23 Pgs Geophysical As Driving means for acoustic marine vibrator
US8094514B2 (en) * 2008-11-07 2012-01-10 Pgs Geophysical As Seismic vibrator array and method for using
US7974152B2 (en) * 2009-06-23 2011-07-05 Pgs Geophysical As Control system for marine vibrators and seismic acquisition system using such control system
US8335127B2 (en) * 2009-08-12 2012-12-18 Pgs Geophysical As Method for generating spread spectrum driver signals for a seismic vibrator array using multiple biphase modulation operations in each driver signal chip
US8446798B2 (en) 2010-06-29 2013-05-21 Pgs Geophysical As Marine acoustic vibrator having enhanced low-frequency amplitude
US8670292B2 (en) 2011-08-12 2014-03-11 Pgs Geophysical As Electromagnetic linear actuators for marine acoustic vibratory sources
US10473803B2 (en) * 2013-02-08 2019-11-12 Pgs Geophysical As Marine seismic vibrators and methods of use
US9645264B2 (en) 2013-05-07 2017-05-09 Pgs Geophysical As Pressure-compensated sources
US9995834B2 (en) 2013-05-07 2018-06-12 Pgs Geophysical As Variable mass load marine vibrator
US9864080B2 (en) 2013-05-15 2018-01-09 Pgs Geophysical As Gas spring compensation marine acoustic vibrator
US9341725B2 (en) 2013-09-20 2016-05-17 Pgs Geophysical As Piston integrated variable mass load
US9360574B2 (en) 2013-09-20 2016-06-07 Pgs Geophysical As Piston-type marine vibrators comprising a compliance chamber
US9618637B2 (en) 2013-09-20 2017-04-11 Pgs Geophysical As Low frequency marine acoustic vibrator
US9507037B2 (en) 2013-09-20 2016-11-29 Pgs Geophysical As Air-spring compensation in a piston-type marine vibrator
US20160327665A1 (en) * 2013-12-30 2016-11-10 Pgs Geophysical As Control system for marine vibrators
US9612347B2 (en) 2014-08-14 2017-04-04 Pgs Geophysical As Compliance chambers for marine vibrators
US9389327B2 (en) 2014-10-15 2016-07-12 Pgs Geophysical As Compliance chambers for marine vibrators
US10488542B2 (en) 2014-12-02 2019-11-26 Pgs Geophysical As Use of external driver to energize a seismic source

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4941202A (en) * 1982-09-13 1990-07-10 Sanders Associates, Inc. Multiple segment flextensional transducer shell
US4764907A (en) * 1986-04-30 1988-08-16 Allied Corporation Underwater transducer
US4706230A (en) * 1986-08-29 1987-11-10 Nec Corporation Underwater low-frequency ultrasonic wave transmitter
US4763307A (en) * 1987-01-20 1988-08-09 Frank Massa Wide-range audio frequency underwater transducer
US4894811A (en) * 1987-05-18 1990-01-16 Raytheon Company Outboard-driven flextensional transducer
FR2688112B1 (fr) * 1988-04-28 1996-10-11 France Etat Armement Transducteurs electro-acoustiques directifs comportant une coque etanche en deux parties.
FR2688972B1 (fr) * 1988-04-28 1996-10-11 France Etat Armement Transducteurs electro-acoustiques comportant une coque emettrice flexible et etanche.
US4932008A (en) * 1988-10-04 1990-06-05 Raytheon Company Hinge-modified flextensional transducer
US4862429A (en) * 1988-10-04 1989-08-29 Raytheon Company Flextensional electroacoustic transducer with hydrostatically compression-loaded driver
US5126979A (en) * 1991-10-07 1992-06-30 Westinghouse Electric Corp. Variable reluctance actuated flextension transducer
US5375101A (en) * 1992-08-21 1994-12-20 Westinghouse Electric Corporation Electromagnetic sonar transmitter apparatus and method utilizing offset frequency drive
NO176457C (no) * 1993-03-15 1995-04-05 Pgs Seres As Drivenhet for akustiske sendere
NO301796B1 (no) * 1995-05-18 1997-12-08 Unaco Systems Ab Drivenhet for akustiske sendere

Also Published As

Publication number Publication date
WO1997041453A1 (en) 1997-11-06
US6041888A (en) 2000-03-28
AU2106897A (en) 1997-11-19
NO961764L (no) 1997-10-31
NO961764D0 (no) 1996-04-30
DE69713169D1 (de) 2002-07-11
NO303472B1 (no) 1998-07-13
EP1015912A1 (en) 2000-07-05

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